June 3, 1920] 



NATURE 



443 



May 17. — M. Henri Deslandres in the chair. — G. 

 Bigourdan : Lechevalier at the Observatory of Saint- 

 Gent'vieve. The co-ordinates of this observatory. — 

 M. Hamy : A particular case of diffraction of the 

 images of circular stars of large diameter. — L. E. 

 Dickson was elected a correspondant for the section 

 of geometry in succession to M. Cosserat, elected 

 non-resident member. — P. Humbert : The general 

 solution of the system which satisfies the function W 

 (x, y).— N. Pipping: A criterion for real algebraical 

 numbers, based on a direct generalisation of Euclid's 

 algorithm. — J. Dracli : The spiral compensator and 

 new problems of the mechanics of regulation. The 

 spiral compensator of M. Guillaume, obtained by 

 addition of a third or a fourth metal to an iron- 

 nickel alloy, is the first example of a solid the elas- 

 ticity of which increases with the temperature. The 

 application of this to the control of chronometer 

 balance-springs is discussed, and reasons are given 

 for supposing that the chronometer will equal the 

 astronomical clock in accuracy. — Ch. Fremont : The 

 genesis of cracks in certain axles. — P. Morin : The 

 study of flow over a weir with the aid of chrono- 

 photography.— M. Battestini : The optimum magnifica- 

 tion of a telescope. The magnification of a reading 

 telescope should be reduced proportionally to the 

 square root of the illumination of the field.— L. 

 Thielemans : Calculations and diagrams of lines carry- 

 ing energy to great distances. — G. Bruhat : The pro- 

 perties of fluids in the neighbourhood of the critical 

 point and the characteristic equations.^ — J. Villey : 

 The discussion of Michelson's experiment. — C. 

 Zengheiis and B. Papaconstantinos : The acceleration 

 of the decomposition of hydrogen peroxide by colloidal 

 rhodium. From measurements of the velocity con- 

 stants the reaction is shown to be unimolecular. If 

 the solution of colloidal rhodium is treated with a 

 current of hydrogen or carbon monoxide the reaction 

 is accelerated.— F. Bourion : The impurities of the 

 benzene extracted from commercial chlorobenzenes. 

 Normal hexane and heptane have been isolated, and 

 also chloroform, from benzene extracted from com- 

 mercial chlorobenzene. — C. Matignon and Mile. 

 .Marchal : The prolonged action of carbon dioxide on 

 silicates and quartz. Six minerals and glass were 

 submitted to the action of a solution of carbon dioxide 

 in water under a pressure of lo atmospheres for a 

 period of ten years and three months. The quantities 

 of silica in solution were estimated, and the minerals 

 after this exposure examined microscopically for 

 evidence of attack. Quartz, wollastonite, mica, talc, 

 dioptase, and asbestos showed signs of corrosion. 

 With glass the corrosion was scarcely perceotible.^ — 

 J. Bouganit and J. Perrier : The action of hydro- 

 cvanic acid on tjlucose : Kiliani's reaction. In solu- 

 tions faintly acid, even as weak as hundredth normal, 

 the combination between hydrocyanic acid and glucose 

 does not take place, and this would also aopear to 

 be the case in neutral solution. .-\ slight alkalinity, 

 even as small as that derived from the glass con- 

 taining vessel, determines the reaction, which is there- 

 fore orobablv between glucose and alkaline cyanide. 

 The reaction between potassium cyanide and glucose 

 was quantitatively studied, and proved to be bimole- 

 cular. — L. Cayeux :. The Hettangian iron minerals of 

 Burgundy. The iron mineral at Beauregard is not 

 oolitic, but the whole of the oxide of iron is a sub- 

 stitution product for calcium carbonate. — Ph. N^gris : 

 The alternatives of the Glacial and inter-Glacial epochs 

 during the Quaternary period. — G. Ferronniire : An 

 Eifel laver of the Basse-Loire synclinal.— .X. Boutaric : 

 The intensitv of nocturnal radiation at high altitudes. 

 — E. Rothi": A new electrical anemometer. For 

 observations of wind velocities at high altitudes the 

 anemometer is carried in a sm^ll captive balloon, and 

 NO. 2640, VOL. 105] 



the. anemometer vane serves as an interrupter, which 

 at each contact puts in action a small electrical oscil- 

 lator. At the base of the cable holding the balloon 

 is a small receiving apparatus for detecting wireless 

 signals. The indications of several instruments fixed 

 at different heights up the cable can be received 

 simultaneously. — G. Andr6 : The exosmosis of the acid 

 principles and sugars of the orange. — P. Bugnon : 

 The structure of certain fibro-vascular bundles in the 

 stems of the Graminaceae. — H. Piston : The variation 

 of the energy as a function of the time of stimulation 

 for peripheral vision. — .A. Mayer, H. Magne, and 

 L. Plantefol : The reflexes provoked by irritation of 

 the respiratory passages. Action of the general 

 exchanges of the organism. The irritation of the 

 terminations of the trigeminal nerve in certain 

 mammals has the effect of causing, for more than 

 half an hour, a reflex diminution of the general 

 exchanges of the organism. These may be lowered 

 to a value verv small compared with the normal. — 

 A. Desgrez and H. Bierry : 'Nitrogen equilibrium and 

 lack of vitamines.— R. Hpvasse : The number of 

 chromosomes in parthenogenetic tadpoles. — M. 

 Delage : Remarks on the preceding communication. — 

 J. Legendre • The food rdgime of Carassius atiratus 

 in Madagascar. 



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